Meet the motorcyclists dedicated to save you from traffic fines.

Imagine the scene. Masked bikers riding through the streets of London in determined pursuit of their quarry. They have names such as Bald Eagle, Parking Warrior and Coco and cover their faces with V For Vigilante masks and communicate via on walkie-talkies. But don't be afraid, they're on your side – and if you drive a car, they may have already saved you a £130 fine.

Meet the NoTo Mob, a group dedicated to fighting what they see as unfair parking tickets and charges. During the week they're normal blokes (and the odd woman). Steve Baker, aka Bald Eagle, is a legal adviser from north London. Graeme Jones, aka Parking Warrior, is an auditor from south London.

But on Saturdays they come together for a common cause. They follow council CCTV cars, or "spy cars", then stand nearby holding signs to warn drivers about the presence of a CCTV vehicle and potential fine if they break the rules.

Motorists pull over, wave or give the thumbs up in gratitude. Complete strangers have been known to hug them in support.

"There are 22 mobile enforcement vehicles within four miles of Charing Cross," says Graeme. "We know where they go, they're creatures of habit."

The NoTo Mob isn't opposed to parking enforcement. It's opposed to what it sees an unfair parking enforcement. The group targets "honey pots" – high-ticket areas with confusing road markings or unclear signs where the CCTV cars are most likely to operate.

Graeme explains: "These honey pots can result in the same driver caught five days on the trot. The first they know about it is when they get the fine through the post. We have to have parking enforcement. But it has to be fair and in proportion."

The NoTo Mob says CCTV cars should be a visible deterrent. So the group makes sure that their presence is highlighted.

Steve feels motorists are being used as cash cows. "I was near a bus lane and asked drivers who pulled over, 'Did you see that sign?' They replied, 'What sign?' They didn't realise. They'd have got a fine if they'd driven down it.

Steve Brown, aka Boyo, is a 46-year-old sound recordist from Hertfordshire. He adds: "When we turn up to warn motorists, the CCTV cars often run back to their base and won't come out to play.

"Everyone's tired of these services being contracted to private companies, local authorities don't seem accountable. We're just a group of like-minded individuals giving our time voluntarily. It's people power."

Most action is in traffic hotspots in and around central London but word is spreading. What started in July 2010 is capturing people's imaginations and steadily gaining support.

A hardcore group – mostly men over 50 – go out regularly to "escort" CCTV-equipped cars. But since featuring on the BBC1 documentary Parking Mad, membership on its forum has grown to 700. Members include a gas fitter and retired diplomat. Cyclists or pedestrians can also join in, while people have even arrived on mobility scooters wearing masks.

"Anybody can do it," says Steve Baker. "We have rules and guidelines for our safety and to ensure we don't get arrested. But we're not doing anything wrong. It's not rocket science, you just need to understand the dos and don'ts and off you go."

If you want the NoTo Mob's help, just go online and ask. Essex, Hertfordshire and Kent have seen recent activity, while concerned motorists want to set up sections in Newcastle, Leeds, Manchester, Edinburgh and Birmingham.

The group also offers help to motorists who have received tickets. They cite one success in central London where signage changed from "no right turn" to "no left turn", resulting in about £54,000 of tickets in one month. They contacted the local authority saying the signage was unlawful, and the money was repaid. In total, they reckon they've got £2.8 million back into motorists' pockets.

Meanwhile, at the end of a long day on the road, you might spot Parking Warrior and Bald Eagle heading into the West End.

"People recognise our masks and cheer and hold up their mobiles to take pictures," says Graeme.

"Sometimes there can be thousands cheering us through Soho on a Saturday evening, it makes you feel good. People appreciate what we're trying to do."